Cam buckle

ABSTRACT

A buckle for fastening belts or straps, such as those used in cargo handling, comprising a substantially U-shaped frame providing a seat for a removable pressure plate having a serrated surface across a large portion of the face thereof. A cam, having a similarly serrated face thereon is biased toward the face of the pressure plate by a spring acting between a cam lever and the frame, so as to hold a strap between the pressure plate and the cam face. The cam may be pivoted away from the pressure plate against the force of the spring by the cam lever which is pivoted on a pin mounted within the frame. The shank of the pin may be upset at one end thereof so as to produce a rivet which becomes firmly held within an aperture in the frame. The aperture is formed within a depression on one of the legs of the U-shaped frame which causes the cam lever to be offset from the leg a sufficient distance to preclude the leg from obstructing the pivotal motion of the lever. Alternatively, the pin may extend through opposite keyhole slots in the legs of the frame. With the smaller portions of the slots at the upper ends thereof, the biasing spring acting on the cam causes the cam to force the pin upwards into the slot to maintain it within the frame.

United States Patent Prete, Jr.

[451 July 25, 1972 [72] inventor:

[52] U.$. Cl. ..24/l91, 24/70, 24/170 [51] Int.Cl. A44b ll/12,A43c 11/00[58] Field of Search ..24/l91, 78, 170

[56] References Cited UNITED STATES PATENTS 2,653,365 9/1953 Elsner..24/170 3,013,317 12/1961 Weber.. ....24/170 3,413,691 12/1968Elsner... 24/170 X 2,916,786 12/1959 Legat 1 ..24/l70 672,793 4/1901Mixer 24/78 UX 632,793 9/1899 Sell et a1. 24/170 2,869,200 1/1959Phillips et a1. ....24/78 3,177,545 4/1965 Svensson ..24/l70 PrimaryExaminer-Paul R. Gilliam At!0rneySmyth, Roston & Pavitt [57] ABSTRACT Abuckle for fastening belts or straps, such as those used in cargohandling, comprising a substantially U-shaped frame providing a seat fora removable pressure plate having a serrated surface across a largeportion of the face thereof. A cam, having a similarly serrated facethereon is biased toward the face of the pressure plate by a springacting between a cam lever and the frame, so as to hold a strap betweenthe pressure plate and the cam face. The cam may be pivoted away fromthe pressure plate against the force of the spring by the cam leverwhich is pivoted on a pin mounted within the frame. The shank of the pinmay be upset at one end thereof so as to produce a rivet which becomesfirmly held within an aperture in the frame. The aperture is formedwithin a depression on one of the legs of the U-shaped frame whichcauses the cam lever to be offset from the leg a sufficient distance topreclude the leg from obstructing the pivotal motion of the lever.Alternatively, the pin may extend through opposite keyhole slots in thelegs of the frame. With the smaller portions of the slots at the upperends thereof, the biasing spring acting on the cam tain it within theframe.

3 Claims, 6Drawing Figures PATENTED JULZSIBR 3,678,542

% @kfA Mix CAM BUCKLE BACKGROUND OF THE INVENTION This inventiongenerally relates to a buckle by means of which the ends of a strap orbelt may be connected to one another for suitable purposes, such as thesecuring of cargo. When articles, hereinafter referred to as cargo forthe sake of simplicity and not limitation, are to be secured in place,it has become common practice to attach a belt or strap either about thecargo or to structural members in its proximity so as to preventmovement thereof. This is particularly important when the cargo is beingtransported in a vehicle.

In order to secure the ends of the belt to one another and to place thebelt under sufficient tension to prohibit movement of the cargo, it hasbecome common practice to provide a buckle to which one end of the beltis permanently fastened and through which the other end of the belt maybe threaded and pulled until the desired amount of tension is present inthe intermediate portion of the belt. Such a buckle has been shown in U.S. Pat. No. 2,998,626, issued Sept. 5, 196i to Prete, Jr.

In designing such buckles, it is important to include the features oflow cost, light weight, high strength, protection of the cargo fromdamage by the buckle, and adaptability to a large number of belt sizes.Many of the prior art buckles have embodied one or more of thesefeatures but no buckle is presently available in which they are allpresent in an optimum combination.

For example, in one prior-art buckle of this general type, the framestructure is formed from a pair of side plates which are held togetherby a plurality of pins, one of which forms the anchor to which one endof the belt is permanently attached. Additionally, a structural memberover which the other end of the belt is passed is fixed between theplates to prevent them from moving toward one another. A cam having aserrated face is positioned so as to hold the threaded end of the beltin contact with the last mentioned structural member under the influenceof a spring acting against the cam. The cam may be pivoted away from thestructural member by a lever which is fixed to the side plates by apivot pin. The plurality of pins all extend beyond the outer surfaces ofthe side plates and are peened thereagainst over washers.

These buckles do not present an optimum combination since the sideplates tend to damage the items being stored because the lower edgesthereof are relatively narrow and come into direct contact with theitems. Consequently, any force exerted by the buckles on the cargo mustbe distributed over a relatively small area and a large amount of damagecould be done with even a moderate pressure or belt tension force.

The ability of such buckles to hold belts in tension has been found tobe lower than that which might be desired since the cam face, althoughit may be serrated, comes into contact with a smooth face on thestructural member over which the belt is threaded. 7 In the prior artbuckles, when the cam lever is pivoted about its pivot pin, it will tendto come into contact with the frame sides and its movement will beobstructed thereby unless one or more washer-like members are positionedover the pin and between the lever and at least one side of the frame.

In summary, therefore, such buckles are relatively expensive tomanufacture since they require an excess amount of hardware, such as theabove-mentioned washers on the pivot pin and the structural pins, do notprovide sufficient belt tension holding strength in all applications,and may cause damage to the cargo.

SUMMARY OF THE INVENTION A buckle formed according to the concepts ofthe present invention comprises a unitary, U-shaped frame whicheliminates the necessity for structural pins to hold side plates infixed relative positions. The channel or connecting portion of the frameprovides a seat for a belt pressure plate which may be formed either asan integral part of the frame or as a separate member which is mountedthereon. The channel also provides a broad surface or large area overwhich pressure forces may be distributed.

The pressure plate is provided with a serrated surface over asubstantial portion thereof so that a cam, having a serrated face, willexert a pressure on a belt in such a position that the belt is held byopposed serrated surfaces.

The cam is biased toward the pressure plate by a coil spring mounted ona pivot pin to act between an integral cam lever, mounted on the pin andthe frame. The pivot pin passes through a pair of coaxial apertures inopposed legs of the frame and one end thereof is upset in rivet-fashionso as to become firmly fixed within its adjacent aperture. The other endof the cam pivot pin will therefore not have to be fixed in any mannersince it is thereby prevented from moving within its aperture.

A very slight indentation in the side of the frame about the aperture inwhich the pivot pin is riveted will cause the cam and its associatedlever to pivot in an arc which passes adjacent to, but cannot beobstructed by, the side of the frame. In other words, this inventionalso embodies the use of an indentation to produce a permanent,frame-created offset of the lever so that a washer between the lever andthe frame is no longer required.

As an alternative, coaxial keyhole slots may be formed in the oppositelegs of the frame with the smaller portion of the slots extendingupwardly. A pivot pin having reduced portions adjacent the ends thereofmay be positioned within the keyhole slots. The above-described cammember is positioned on the pivot pin and a coil spring acts between thecam and the frame so as to bias the cam toward contact with the pressureplate. Thus, as the cam tends to be rotated by the spring, it actsagainst the pressure plate so as to force the pivot pin up wardly due tothe tendency of the cam to rotate about its cam surface. This preventsthe pivot pin from inadvertently being removed from the frame. Further,when a belt or strap is positioned between the cam and the pressureplate, the force exerted to hold the pivot pin in place is increasedstill further since the center of rotation of the cam, at its cam face,is thereby moved still closer to the upper end of the keyhole slot.

Intermediate the ends of the frame, the channel may be cut away to allowthe end of the belt to be positioned between the pressure plate and thecam. At the opposite end of the frame, a second end of the belt may bepassed over the channel, positioned over itself in overlapping fashion,and sewn in place along the overlap.

This latter feature reduces the pressure exerted by the buckle on thecargo which is being secured in place since, if properly positioned, thebuckle frame will never enter into contact with the cargo but instead,will be separated therefrom by the belt. In other words, a relativelysoft material is positioned between the cargo and the frame so as toboth distribute the forces over a large area. and to absorb some of theforces through compression.

Alternatively, a pin may be mounted in any suitable fashion such as thattaught in the prior art or in the same manner in which the firstdescribed pivot pin is mounted. This pin, of course, is an alternatemethod of permanently attaching a. second end of the belt to the frame.

If desired, broad longitudinal channels or ridges may be formed in theframe channel or central section so as to increase the rigidity of theframe without adding structure or weight to it.

The buckle is rigid and is precluded from damaging cargo due to itsU-sha is less expensive due to its unitary manufacture, the reduction ofthe number of parts, and the novel system by which the parts are fixedtherein, and is versatile in that a wide variety of belt sizes may byutilized within a single buckle.

Other advantages, objects, modes, and embodiments of this invention willbecome obvious to those skilled in the art through perusal of theDetailed Description and accompanying drawing which illustrate what ispresently considered to be a preferred embodiment of the best modecontemplated for utilizing the novel principles set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a side elevation of a buckleformed in accordance with the present invention;

FIG. 2 is an end view of the buckle shown in FIG. 1, taken along a lineII-ll thereof;

FIG. 3 is an end view of the other end of the buckle shown in FIG. 1;

FIG. 4 is a top plan view of the buckle formed according to the presentinvention;

FIG. 5 is a side view of a pressure plate formed according to thepresent invention; and

FIG. 6 is a side elevation of a buckle formed in accordance with analternate embodiment of the invention.

DETAILED DESCRIPTION Referring now to the drawing ingreater detail,there is shown a buckle generally designated 11 to which a first end 13of a belt is permanently attached and through which a second end 15 ofthe same or a difl'erent belt may be threaded for cargo hold-downpurposes, as previously described. The frame generally comprises aunitary, U-shaped member 17 having opposed upstanding legs and a firstand second central or channel portion 19 and 21.

The first end 13 of the belt is permanently attached to the buckle bymeans of the second channel portion 19 over which the belt is passed sothat it may be sewn to itself, such as by stitching 23. A pin can befixed to the upstanding legs of the frame in any suitable manner, suchas by spring clips or by peening the ends thereof over washers. However,the pin can also be firmly attached to the frame by upsetting an endthereof in a manner similar to which a rivet might be upset, causing theend to expand within an aperture in the adjacent frame leg. In thismanner, the pin is firmly held within the frame against axial movementthereof by means of the upset end.

A notch 33 is formed in the central portion of the channel 19 so thatbelt end 13 may extend around channel portion 21 and the end 15 of thebelt may be threaded into the buckle in the manner illustrated inphantom in FIG. 1. As shown in both FIGS. 1 and 5, the forward portionof the channel 19 provides a seat for a pressure plate 35 havingserrations or grooves 37 over a large portion of the face thereof andagainst which the belt is seated. Of course, the pressure plate could beformed as an integral portion of the frame, if desired, butit has beenshown as a separate piece here due to the fact that the slight degree offreedom of movement it has within the frame allows it to be adjustedtherein by the belt so that the belt is in contact with nearly all ofthe serrations 37 regardless of the specific angle which it may assumeas it passes through the buckle. Further, since the plate has somefreedom of movement, it compensates for mis-match which may occurbetween the parts as a result of manufacturing tolerances. A pair oflegs on the plate in contact with the first channel portion 19 preventinadvertent removal thereof from the buckle. Full depression of the camlever will allow installation or removal of the plate unless a belt isthreaded between the plate and the cam, in which case, the plate iseffectively locked into position.

A pin 41 is passed through coaxial apertures in the upstanding legs ofthe frame and an end 43 thereof is upset in the same manner in which arivet would be upset, causing end 43 to expand within its associatedaperture so that the pivot pin 41 is firmly held in the frame againstaxial movement. It is also prevented from bending or moving in adirection parallel to the force exerted by the belt when it is intension since it extends through a coaxial aperture on the oppositeframe leg.

A lever 45 is pivoted on the pin 41 so that when an operator exertspressure against a portion 47 thereof,the lever will pivot in thecounterclockwise direction (as viewed in FIG. I) against the force of aspring 49 acting between the forward channel portion [9 and the lever.Spring 49 also serves to prevent the adjacent portion of the lever fromcontacting the adjacent frame leg when pivoted about pin 41.

A serrated cam face 51 on the forward end of the lever 45 is forced bythe spring 49 toward the serrated face of the pressure plate 35 so thatwhen the end 15 of the belt is passed through the buckle, it is firmlyheld between the serrated cam face and the serrations 37 on the pressureplate. Tests have shown that the provision of opposed serrations on thecam and pressure plate increase the buckle's ability to withstand belttension pulling force by a very significant factor.

When it is desired to remove the end 15 from the buckle, the lever maybe pivoted against the force of the spring 49 by the operator, causingthe serrated cam face 51 to pivot away from contact with the belt 15allowing it to be drawn from between the cam face and the pressureplate.

Face 51 on the cam is manufactured to be of an increasing radius (seeFIG. I) so that a belt of nearly any thickness may be held between thecam and the pressure plate. Thus, the thinner the belt is, the furthercam 5 I will rotate under the infiuence of spring 49. Due to thisfeature, a belt cannot be pulled out of the buckle unless lever 45 isfirst depressed since the pulling force will tend to pull the cam facecloser to the pressure plate and exert a larger gripping force on thebelt.

It is normally desirable to cause the pressure plate and the cam face tobe as wide as possible so that a maximum area of contact between theirserrations and the belt is effected. It is also desirable that the camlever be as wide as possible so as to prevent discomfort to the operatorwhen he depresses it to release the belt. In other words, it isdesirable to provide the cam and its associated lever to be onlyslightly smaller than the distance between the inner surfaces of theupstanding frame legs. However, in order to prevent the cam lever fromcoming into contact with the legs of the frame, some means must beprovided to ensure clearance therebetween. As stated previously, thespring 49 tends to prevent the lever from contacting one side of theframe, thereby ensuring clearance on the side upon which the spring ispositioned.

In order to prevent the opposite side of the lever from entering into abinding or obstructive contact with the other leg of the frame, a smallindentation 52 may be formed therein so as to produce an offset in thatleg. The indentation forces a sufficient amount of metal on the insideof the frame leg to be forced toward the cam lever so that the long sideof the cam lever is prevented from entering into contact with the leg.In other words, the deformation 52 about the pin 41 will produce asufficient offset of the frame in that area to provide satisfactoryclearance between the cam lever and the frame leg. Thus, there is nonecessity to increase the cost of the buckle by installing a washerbetween the lever and the frame leg.

The central or channel portion 19 of the frame may extend entirelyacross the frame on a single plane or, if desired, may be deformed so asto provide ridges or channels 53, in either the longitudinal ortransverse direction, which will further serve to strengthen the frameand ensure its rigidity.

Referring now to FIG. 6, an alternate embodiment of a buckle formed inaccordance with the principles of the present invention has been shown.In many respects, the buckle of the alternate embodiment is identical tothe embodiment previously described and, where possible, identicaldescription labels have been utilized and no further description ofthose parts is necessary.

As shown in FIG. 6, a keyhole slot, generally indicated at 71, is formedin each of the upstanding legs of the U-shaped member 17 so as to be incoaxial relationship with one another. A pin 73, upon which the cam 45is pivotally mounted, is passed through the enlarged portions of thekeyhole 71 until portions of the pin having reduced radii are alignedwith the upstanding legs. The spring 49, mounted on the pin 73, actsagainst the cam lever 45 and the second channel portion 21 so as to urgethe cam into clockwise rotation about a moving center of rotation on itscam face. This causes the pin 73 to be forced upwardly into the reducedportion of the keyhole slots 71 so that the portion of the pin 73 havingreduced radii enter into contact with the walls of the keyhole slot soas to prevent axial movement of the pin. Reference to the figure willalso indicate that when an end of a belt is positioned between thepressure plate 35 and the cam face, the spring biasing of the cam willexert even greater force on the pin 73 due to the efiective alterationof the movable center of rotation of the cam.

On the opposite end of the frame, a pin 75 may, if desired, be passedthrough coaxial apertures in the upstanding legs so that the end 13 ofthe belt may be passed thereover so that it may be removed from thebuckle if desired. in order to accomplish this, the pin 75 may bemounted in any suitable fashion such as by means of a snap ring 77, awasher as taught by the prior art, or, if desired, by upsetting one endthereof in a manner similar to that previously described with referenceto pin 41 in the discussion of the first embodiment.

Thus, the applicant has provided an embodiment of a new and improvedconcept in the buckle art which yields a true advancement in that artdue to the provision of the desirable features previously enumerated.Many modification, alterations, and alternate embodiments of theinvention, without exceeding the scope of the following claims, will beobvious to those skilled in the art; wherefore what is claimed as theinvention is:

lclaim:

l. A buckle for removably holding a strap end including a channel memberhaving a central portion extending along the length of said channelmember and defining a pressure plate receiving means formed adjacent oneend of said channel member,

a pivot means mounted on said channel member in a fixed positionrelative to said pressure plate receiving means,

a pivotable member mounted on said pivot means and including a cam face,in eccentric relationship to the axis of said pivotable member, at oneend of said pivotable member and a lever means at the opposite end ofsaid pivotable member, said pivotable member being freely rotatableabout said pivot means, in a first direction,

a pressure plate loosely seated and freely floating upon said pressureplate receiving means including means on said pressure plate forremovably seating and retaining said pressure plate on said pressureplate receiving means, and

means for biasing said pivotable member about said pivot means in saidfirst direction to force said cam face against said pressure plate,thereby holding said pressure plate in a seated position on saidpressure plate receiving means and preventing further rotation of saidpivotable member in said first direction. 2. The buckle of claim 1wherein said channel member includes a pair of upstanding side walls atthe sides of said central portion, at least one of which has an inwardlydirected deformation about the location in which said pivot means ismounted therein, whereby said pivotable member is prevented from bindingagainst said side walls during rotation about the axis of said pivotmeans. 3. A buckle for connecting two strap ends comprising a firstmember comprising a frame having a first end, a second end, a centralchannel portion extending between said first and second ends, but havingan open interval intermediate said first and second ends and a pressureplate receiving section extending from said one end to said openinterval, and an opposed pair of upstanding legs integral with saidcentral channel portion, a second member comprising a pivot meansmounted to extend between said pair of upstanding legs above saidcentral! channel, a third member comprising a lever means pivotallymounted on said pivot means and having a cam face thereon in eccentricrelationship to the axis of said pivot means and a pressure area thereonupon which an operator may exert a force to rotate said lever about saidpivot means, said lever means being freely rotatable about said pivotmeans as limited only by contact thereof with the extremities of saidpressure plate receiving section a fourth member comprising a pressureplate removably insertable over said pressure plate receiving sectionand including means on said pressure plate for allowing said pressureplate to be freely movable in all directions, within predeterminedlimits, relative to said pressure plate receiving section, as well as tobe removable therefrom while retaining said pressure plate in a seatedrelationship on said pressure plate receiving means, and a fifth membercomprising means for biasing said lever means about said pivot means toforce said cam face against said pressure plate, thereby seating saidpressure plate against said pressure plate receiving means. i

I k t il i

1. A buckle for removably holding a strap end including a channel memberhaving a central portion extending along the length of said channelmember and defininG a pressure plate receiving means formed adjacent oneend of said channel member, a pivot means mounted on said channel memberin a fixed position relative to said pressure plate receiving means, apivotable member mounted on said pivot means and including a cam face,in eccentric relationship to the axis of said pivotable member, at oneend of said pivotable member and a lever means at the opposite end ofsaid pivotable member, said pivotable member being freely rotatableabout said pivot means, in a first direction, a pressure plate looselyseated and freely floating upon said pressure plate receiving meansincluding means on said pressure plate for removably seating andretaining said pressure plate on said pressure plate receiving means,and means for biasing said pivotable member about said pivot means insaid first direction to force said cam face against said pressure plate,thereby holding said pressure plate in a seated position on saidpressure plate receiving means and preventing further rotation of saidpivotable member in said first direction.
 2. The buckle of claim 1wherein said channel member includes a pair of upstanding side walls atthe sides of said central portion, at least one of which has an inwardlydirected deformation about the location in which said pivot means ismounted therein, whereby said pivotable member is prevented from bindingagainst said side walls during rotation about the axis of said pivotmeans.
 3. A buckle for connecting two strap ends comprising a firstmember comprising a frame having a first end, a second end, a centralchannel portion extending between said first and second ends, but havingan open interval intermediate said first and second ends and a pressureplate receiving section extending from said one end to said openinterval, and an opposed pair of upstanding legs integral with saidcentral channel portion, a second member comprising a pivot meansmounted to extend between said pair of upstanding legs above saidcentral channel, a third member comprising a lever means pivotallymounted on said pivot means and having a cam face thereon in eccentricrelationship to the axis of said pivot means and a pressure area thereonupon which an operator may exert a force to rotate said lever about saidpivot means, said lever means being freely rotatable about said pivotmeans as limited only by contact thereof with the extremities of saidpressure plate receiving section a fourth member comprising a pressureplate removably insertable over said pressure plate receiving sectionand including means on said pressure plate for allowing said pressureplate to be freely movable in all directions, within predeterminedlimits, relative to said pressure plate receiving section, as well as tobe removable therefrom while retaining said pressure plate in a seatedrelationship on said pressure plate receiving means, and a fifth membercomprising means for biasing said lever means about said pivot means toforce said cam face against said pressure plate, thereby seating saidpressure plate against said pressure plate receiving means.